To Be Assassin
by Eternal Princezz
Summary: Sawada Tsunayoshi, 21 years old, Vongola Decimo and the bearer of one of the Tr-Ni-Sette, had died on a battle field between Vongola and San Lorenzo. However, waking up on a room that he had left for years was not something he expects. It was the same room he had lived for 14 years, located in Namimori. Just what had happen? Full summary inside
1. Chapter 1

**Title:** To Be Assassins **  
Pairing:** Undecided (SLASH), Past!R27  
 **Rating:** T  
 **Genre:** Friendship  
 **Summary:** Sawada Tsunayoshi, 21 years old, Vongola Decimo and the bearer of one of the Tr-Ni-Sette, had died on a battle field between Vongola and San Lorenzo. However, waking up on a room that he had left for years was not something he expects. It was the same room he had lived for 14 years, located in Namimori. Just what had happen? What was more bizarre is, he found out that 70% of the moon had been destroyed. Just what kind of world he had land on?  
 **  
Chrome:** NightSky-sama, I didn't see boss.  
 **NightSky:** Hmm, I don't know what you are talking about. *CRASH*  
 **Chrome:** That sound...  
 **NightSky:** No! There's nothing there! Just my cat crashing on my things.  
 **Mukuro:** You lied.  
 **NightSky:** *sweating*  
 **Hibari:** I'll bite you to death for lying.  
 **NightSky:** Then, I leave the disclaimer to you Tsuna. * Run from the demon prefect*  
 **Tsuna:** Huh. Chrome, I'm here the whole time. *Being ignored* Huh... well, whatever. NightSky-san didn't own KHR and ACR. *CRASH* *Yells*  
 **Hibari:** Come here so I can bite you to death!  
 **NightSky:** On with story! Kyaaaahhhh!

* * *

 **Chapter 1**

 **Chirp! Chirp!**

A sound that he had missed to hear. When was the last time he heard the birds chirping happily? He can't remember. What he remembers was the sound of gunshot everywhere.

 **Rrrriinggg!**

Unconsciously, his hand retracted from under the duvet and slam on the poor clock. Pulling the duvet from his head, he opens one eye. He grimaced as he touched his heart where he was shot at. He watched the ceiling for two minutes as the gears on his brain start functioning. The first word he said:

"Where the heck am I?"

He sits on the bed, clutching his head that's hurting like hell. One question lingers, unanswered.

"Why am I alive?"

Yes, why is he alive? He still remembers what had happen. A war between Vongola and San Lorenzo, the death of his father, Sawada Iemitsu and his guardians and many more. And finally, _him. He_ was the last person who had protected him, the person who had loved him. Reborn, jis tutor and his lover was the last one who had died in front of him.

All of them had died. Died while protecting the Decimo. Him.

"Heh, even though I'm the Decimo, I'm the one who being protected." He chuckled bitterly. Images of his precious family, guardians and tutor played in front of him. The smiles, laughter, fighting; he missed all of it.

Tsuna watched the rising sun.

A new day and a new world.

A sigh. He let his eyes drift around the room. It was the same room he had lives since his younger days. A photo frame on the desk catches his attention. He walks towards it and grab the frame. It was him with his mother. He gave a longing smile, brushing through the frame. His mother had known about him being in the Mafia – not before she gave hell towards his husband after knowing it.

After a while, he sees something on the desk, shining. It was a ring. A ring that he had wears every time and every second. It was the ring that Reborn had given him, the same day he had confess to him. Tsuna of course happy, so happy that he could _die of happiness._

Just remembering about it, is enough to make the dam he had hold to broke. He clutched the ring like it was his life line, sobbing while repeating his lover name.

He wants him.

After an hours of breaking down, he finally calm down. **Dame-Tsuna, the Boss shouldn't show weakness towards anybody.** He remembers what Reborn had said. **Well, you always had place if you want to cry, with me that is.** His smiles grew fonder. Reborn had always been the tease one and he always fell helplessly with it. After another set of exhaling and inhaling, he tried to sort of his mind for now.

After that, he take a look on his desk, there's computer and laptop on the desk, a sheets, and USB that he rarely saw. A 'Ping!' sound come from the computer made him diverted his eyes towards it.

New mail just comes.

He stared at it before deciding to open it.

From: Unknown  
To: HackerCielo27  
Subject: None

 _Thank you for giving us the information. As promise, we have transfer the pay to your account. Until next time._

Tsuna look at the mail for a minute as the thought of him being a hacker in this world invaded his mind. Sighing, he closed the mail before opening the folder from the computer one by one. Each folder consists of information that higher-ups couldn't get in. He frowned when there is picture attached to each of files he had open. They are various kind of crime.

Smuggles, thief, drug-dealer, human-trafficking, parent's abuse, etc. This is not something he likes to see. But, as he was the Vongolo Decimo in his previous world, he had seen all kind of crime and he had stopped almost all of it. He open more and more folder and grew disgust at each of the information.

But, there is one folder that really catches his attention. It was about the moon being destroyed by some kind of Yellow Octopus creature. Is that even possible? Well, if he thinks more of it, what kind of people had fire on their head but didn't get burn by it? So, he just thinks of the possibility of some yellow octopus creature exist is possible.

* * *

It's already afternoon when he stopped looking at the computer. The angry growls on his stomach are the sign for him to stop and just eat to ease his stomach. When he go towards the kitchen, he can felt how empty the house is. In his previous world, hei old home in Namimori would be already full with bickering from the kids, Lambo, I-Pin and Fuuta, with Bianchi profuse his love towards Reborn – of course Reborn ignore it. And when they had move to Vongola mansion in Italy, the bickering, fighting, laughing and crying had been their daily life.

Tsuna let out a smile as he cooked some simple Omelet for him.

* * *

That evening, after he had his brunch, something happen.

The memories of this world Sawada Tsunayoshi suddenly attack him. Too many information and too many memories had come like a machine gun being shot at his head. Can't take any more of it, he collapsed on the dining room. When he wakes up, the sun already set at the horizon. It's been seven hours since he faint.

He groans.

He didn't know that this world Sawada Tsunayoshi was a loner despite being a hacker and assassin. This world Sawada Nana was admitted to the hospital due to stress, anorexia and depression. It was months ago he visit his mom. He should apologize after this, even though it's not his fault at all.

His circle of friend is limited or should we say there's only one person. Tsuna was of course surprised by the information he get, his friend was – is – Karasuma Tadaomi from the Ministry of Defense. At first, he thought, what kind of friend he is if this Karasuma person is from the Ministry of Defense? Another puzzle that made his head wants to explode right there and right now.

As night soon comes, he's tired already. Wake up in a parallel world, being a hacker an assassin, memories of this world Sawada Tsunayoshi and information had finally get the better of him. He just wants to rest now. Had good night sleep.

When suddenly his phone ringing.

He cursed at whoever had invaded his sleeping time. Answering it with a gruffer voice.

 _"_ _It looks like I'm interrupting your sleep, Sawada?"_

 _"_ _Hell yes you are…"_

 _"_ _Well, I'll make it short then."_

Tsuna wait for this mission. How he knows it's a mission? Because it's _that person_ who had called him.

 _"_ _What mission this time Karasuma?"_

 _"_ _Become a teacher at Kunugigaoka Junior High School."_

That wake him up.


	2. Chapter 2

**Disclaimer:** I don't own Katekyo Hitman Reborn and Assassination Classroom. Only own the plot and story. If I own, it'll be turning into Yaoi! Lol

 **Special thanks to:** ColorlessRainbow42, Yui Velsaria, Poosa-ard, nanobb, Amatsu No Shinsei, Miguel Dragneel, absolutedespair, nellin, China12, Syhmera, Fiane-Fiamma, Chaos Morningstar, allen109, INSECTgrl for following this story!

 **Chapter 2**

Tsuna stood in front of the building with symbol of 'END' on top of the hill. The building look like it would topple over if a bulldozer knocks over it. Not to mention, the places look like wreckage. The field is cover with grass like it's never been clean of for ages, the flowers pot is full with wilt flowers, and so on. This place is suitable enough for any ghost adventure or ghost hunting live show.

He sighs. If he's still the Decimo, this place would have been clean already, through and through. No students should study in this kind of environment and he knows how they can't concentrate. He already experiences this when Reborn had him with his guardians to study near garbage, stinking drain and all.

 ** _"_** ** _If you go undercover, there's no such thing as nice places you can hide. Whether it is a drain, garbage, polluted factory; you choose it. Except, you go undercover as a waiter, bodyguard or civilians. So, right now and right here, you should train yourself to block any kind of smells and just concentrated on the work I have given. If I see any mistake, you better pray that you don't want to be born in this world."_**

After that, Tsuna and the others had done the work without any mistake at all. Knowing Reborn, it would be a torturing time if any mistake were spot.

Tsuna smiled at those memories. But right now, he should save it at the back of his mind since it's time for work.

He slide open the door and inspect the inside of the building. Not bad. The inside is clean than the outside. Since he comes early than the student and teachers, the building is dead silence except for birds chirping and crickets. He looks at the classroom. There are 26 students, three teachers with two humans and one yellow octopus. Moreover, all of them are train in assassination just to kill the yellow octopus.

"Did he really destroy 70% of the moon?" Tsuna murmured. Because for him, no matter how hard he tries to think about it, his Hyper Intuition would just flare up and said it's not the whole truth. "I should find some information about this."

After satisfying of what he had seen, he exits the building and walk down the hill to go to the Board Chairman office.

Asano Gakuho is not your typical guy. He is nice but with that kind of twist mindset, he is no better than a murderer himself. Tsuna had made his research of this man and what he had find, was something that had disturb him even in sleep. His kind of teaching the students really ticks Tsuna off. Asano was the one who created the Class E system, under the thought that having someone to discriminate makes one progress more. His aim is to create a world where 95% of people work and 5% of people are lazy.

Asano also willing to take his educational methods to the classroom by giving them personal lesson and later supercharging the final exams to be akin to a college or university exam and purposely excluding Class E just to ensure that they do not pass. His lack of care towards his students and sees them as tool is a solid prove that he had little morality inside of him.

Tsuna knows that if he meets this man, he really should be careful. Seeing how the upper-up also are scared of him shows that he had high influents.

He looks towards the Board Chairman door. He should present himself orderly. Straightening his suit and retying his tie in a second. He knocks on the door three times before a commanding voice boom from inside of the room. He enters with his head held high.

* * *

As soon as Asano see the man or should he say teen, he sense power, more than he had. "Sawada Tsunayoshi-san." The teen nodded his head. "So, I presume you want to be a teacher, seeing your resume."

"I am." And before Asano can continue with his speech, Tsuna talk first. "I want to be a teacher in Class E." That is something Asano can't debate with, seeing the determination on the younger eyes, and he didn't denied that he felt a little bit scared just to be under this Sawada Tsunayoshi's gaze. So much power in it that he can't compete with it.

"I see, and I welcome you to Kunugigaoka Middle High School, ."

"Thank you Board Chairman."

"Please, just call me Asano."

"Then, thank you, Asano-san."

* * *

Tsuna lean his back on the tree, waiting for his friend, Karasuma to come and meet him like they had promise last night. Pocketing one of his hands, he looks up at the sky. The sun is already up few hours ago and the cloud already moving back and forth, never stayed in one place.

 ** _"_** ** _I'M EXTREMELY HOME SAWADA!"_**

 ** _"_** ** _Onii-san, welcome home. How's your mission going?"_**

 ** _"_** ** _IT'S DOING EXTREMELY GOOD! I HAVE EXTREMELY GOOD FIGHT TOO WITH THE ENEMY!"_**

 ** _Tsuna smiles as he hears more about the mission from his Sun Guardian, Sasagawa Ryohei._**

 ** _"_** ** _Herbivore, I'll bite you to death for being loud."_**

 ** _"_** ** _Kyoya…"_**

 ** _"_** ** _EXTREME HIBARI! THIS IS HOW I EXTREMELY USUALLY SPEAK!"_**

 ** _Tsuna, who saw that his Cloud Guardian is not in the mood, hurriedly calming the two. "Calm down you two and please don't fight inside of my office. There's too many paperwork's that I have done that Hayato-kun still didn't take." The two calm down with Hibari comment 'Hn' . "Onii-san, you should go and rest for now. Kyoko-chan had missed her brother too." With final salute and loud EXTREME, Ryohei run to find his beloved sister._**

 ** _Tsuna look at his aloof Cloud and smiles. "Did you and he spar again?" Kyoya just keep his lip tight but nodded. "And let me guess, you lose again?"_**

 ** _"_** ** _Hn."_**

 ** _"_** ** _Kyoya, you know how strong he is not to mention this is Reborn we're talking about, who had ages of experience than us who only have a decade." Tsuna tried comforting him. "Don't worry too much Kyoya, I believe you'll win against him someday."_**

 ** _With that, Kyoya turn around, attempting to exits the office. He stops just before he open the door and with a soft voice, he says "Thank you..." Tsuna saw the slight upwards on Kyoya's lips before he exits the door._**

 ** _"_** ** _Tsundere much, Kyoya."_**

The memories of his Sun and Cloud guardian made him slightly emotional and before someone see it, he brushed away the tears from the corner of his eyes. Tsuna then heard a twig been stomped from behind him.

"Good morning, Karasuma."

"Good morning, Sawada. You're early, as always." Karasuma said as he stands beside the younger.

"Can't let my image as a teacher gets bad you know."

"Hmm, you and your narcissistic self, I really don't know what to do about it." Karasuma comment. "So, did you meet the Board Chairman already?" Karasuma leaned on the tree where Tsuna just lean earlier.

"Yeah, and I already hate him." Tsuna said, leaning beside the taller man. Somehow, talking with Karasuma is easy. It's not awkward despite of him meeting this man for the first time. Maybe the memories he got from this world Sawada Tsunayoshi had made him feels like that. He's happy that there's someone he can talk too in this world – even though frankly, he missed his famiglia so damn much and Reborn too.

"Well. I know how you feel. My first time meeting him also was same as you." Karasuma said. "Well then, ready to become a teacher, ?" Tsuna rolled his eyes hearing it.

"Oh, please, don't call me that, Karasuma."

"Hmm, whatever you say. Let's go, class will start at any moment now."

And with that, they walked towards the building where students of Class E already flocked inside. Karasuma told him to wait outside as he'll announce it to the students. Tsuna wait outside while straightening his suit. After a few minute, Karasuma finally call for his name to enter the classroom.

Welp, it's time.

* * *

"Listen up, as of today; this class will get another teacher who'll assist you all in anything. Please enter, Mr. Sawada..."

Nagisa tilted his head to the side when he hears about a new teacher being located here, the Class E. Is the new teacher an assassin like Bitch-sensei? Did this new teacher get send here to kill Koro-sensei also? When he looked at Kayano, the girls just shrugged and Karma just smile gleefully. _"He had found another target it seems."_

As the teacher come inside, what greet them shock them. There's no way this kind of teacher is an assassin like Bitch-sensei is. Just looking at his face, they already made an assumption that this teacher couldn't even hurt a small ant.

"Hello and good morning to all of you. My name is Sawada Tsunayoshi, and I'm your new teacher starting today. Nice to meet you."

* * *

 **Fast update! Ok, I think I overdid it. Karasuma really OOC here but since this is my story, I'll make it like that. I'll stick to it. But do not worry, I won't make it too OOC, it's just the relationship between Tsuna and Karasuma. They are friends and can you think of friends ignoring each other even though they were literally standing just beside each other? NO! Except if you really had a problem with that friend. Anyway, I really hope you like this story. Since this is my first attempt on writing Crossover, please and please guide me. I'm new!**

 **Oh, and don't forget to click the Follow, Favourite and Review button! I would totally appreciate it.**


	3. Chapter 3

**First of all, this is SHOUNEN-AI or YAOI. I already hint it on chapter one and at the pairing but as of the moment, they will be none of it. My story will focus more on action and what will they do regarding all of this situation and how Tsuna will teach his students. So, romance for now is 'Nuh-uh' except for past reference where Tsuna will remember about his old life.**

 **Also, there's one important thing I forgot to tell you all. The timeline of my story. Assassination Classrom will begin at when Ritsu already transfer at the class but before Horibe Itona transfer, somehow in between this timeline. So, any question regarding my story, just ask me and I'll try my best to answer it.**

 **For now, enjoy reading!**

 **Disclaimer:** I don't own Katekyo Hitman Reborn and Assassination Classroom. Only own the plot and story.

 **Special thanks to:** CrazyManhwaGirl, Knight Yuuki, hongvo321, puppyclaw.x, vidoan200, Soraflame, The SENDER and the TRAVELER, Yume Masure, Seithr-Kairy, Evil E. Evil, flora25090, Wxin, AnkhseramFT, Plew A.E, eeveelutionlover2000, HermioneX, LunaLivesInTheClouds, team1225, ZeAwsumOtaku, Ren-chan the otaku, , The 27th Noah, Maria Aizabelle373, nanoidManicist, Lectric assidue, Claire nunnaly, Mo-Freakin, FlashDevil, IrogicalArgument, hamysophie2910, nusyafizzul, xxdarkxxalicexx, katsuchan21, AkatsukinoRuby, YuutoYuuichi, kage kitsune 14, Artist Magician, anionymm, Natsu Dragneel 777, Silverheart33, Fuyuki Merleawe, .927, AkiHime20, EmiWorm, Darkestshadow Brightestlight, Shuugugaku, Shouen, Neko1290, BeingLovexx, Haruki Ryuu, Syafiq, Artist of Ran, Bookwork54321, MikazukiSuzuki, nakie, Aravel, Bianei, thecatleader **(58 follow in chapter 2?! You guys rock!)**

* * *

 **Chapter 3**

 _"_ _Hello and good morning to all of you. My name is Sawada Tsunayoshi, and I'm your new teacher starting today. Nice to meet you."_

Tsuna's first impression of his soon to be students are, they're bunch of kids. How can the government be so stupid to give this kind of mission of assassination to mere students, a fucking 15 years old student? No matter how skill they are on this field, there are limit for them. Students like them should focus more on their studying not killing a yellow octopus just to save the world. This is too much even for Tsuna.

Yes, he becomes a candidate for Mafia boss at the age of 14, but still, he didn't kill at that time. He was taught how to become a perfect boss for the famiglia, learns self-defense, and learns how to protect your own famiglia. It's all about learning. Even as a Decimo, he never killed anyone except necessary. But this? God, even he can see some naïve and innocents look inside of their eyes. He didn't deny the facts that some of them had the skill to be assassins just like Takeshi.

But, can't they give this kind of mission towards some professional adults?

"So, how was it, the class?" Tsuna turn from his position where he was leaning on a window sill, looking at the students trying to kill Koro-sensei with a cup of espresso on his hand.

"Not bad but I don't like it." He sipped on the espresso. "Making a child doing such preposterous mission like this somehow made me want to strangle the government people. No offense though, Karasuma."

"It's okay, I know what you feel. I never want those brats to do this assassin mission too but who am I to oppose the higher up. I am just someone who is under them and I can't do anything except to accept this mission." Karasuma sighed as he leaned on the chair.

Tsuna chuckles as he sees Karasuma stressing like that. "What's wrong, age catching up already? If you frown like that, your face will end up with wrinkle all over."

"I forgot that you're a brat also." Karasuma grumbled as he watches Tsuna smirking towards him.

Tsuna drink his espresso as his attention turn back towards the students and Koro-sensei and sweat dropped when he saw that Koro-sensei had made a mistake which the students had taken advantage at to shoot at him.

 _"_ _Haha, just like my guardians."_ He thought.

* * *

Tsuna watched the students waving at each other as the school had end for the day. He was left alone at the teacher lounge. Karasuma had been called by the government to discuss about a possible assassin to transfer to the class.

He leaned his head back and let out a deep sighed as he felt the exhaustion eating up his stamina. If Reborn were there, he will be nagged on how weak his body had been and maybe he'll add a Spartan training to shape up his body again.

"Nurufufufu, Tsunayoshi-kun, what are you doing here?" Tsuna open his eyes (when did he closed his eyes again, he didn't knew) and saw that Koro-sensei was looking down at him with his forever wide smiles. (It's kinda creepy that Tsuna thought he just saw a creepy yellow octopus was staring at him)

Tsuna leaned forward as he stretched his hands up. "Tsuna..." Koro-sensei looked at him. "Just call me Tsuna, Koro-sensei. Tsunayoshi is too long." He said, smiling at the suddenly teary Koro-sensei. "Why are you crying?"

"This is the first time somebody being nice with me." Koro-sensei said as he wiped imaginary tears with a handkerchief. "The others would probably greet me while shooting or stabbing at me."

 _"_ _Well, you're their target, so of course they'll be taking any advantage or openings they see."_ Tsuna sweat dropped but smiles afterwards. "Well, it's kind of not their fault for greeting at you like that. It's just; you're their target is all."

"Nurufufufu, but they'll never catch me though." Koro-sensei smiles get wider as green stripes appear on his faces.

Tsuna narrowed his eyes that made Koro-sensei sweating bullets. He scrutinized him.

"What kind of UMA are you?"

"..."

"..."

"How rude! I was born and raised on earth you know!" Koro-sensei loses his composure with his tentacles flaing all over the place that made Tsuna laugh.

"I know, I'm just teasing you, Koro-sensei." Tsuna said. "I didn't know that you'll really get mad if someone asked about it."

"That's not nice Tsuna-kun." Koro-sensei said as he makes a mess with Tsuna's gravity defying hair.

"So, if you were born and raised on earth, I assumed you were once a human then." Tsuna said it carefully since his Hyper Intuition is telling him to be careful with this kind of question. Tsuna looked at Koro-sensei who had a – poker face?

"What are you talking about? I am like this from the beginning."

"Lie." His Hyper Intuition tells him that it is a lie and his HI never once wrong in telling him true and false information.

"..."

"Nurufufu, do not worry about that kind of situation though you'll know about it one day."

"Then..." Tsuna stand from his seat. "Promise me that you'll be the one telling me about your identity. I don't like hearing from others mouth since it can be lied."

"Nurufufufu, of course." Koro-sensei patted his head. "Then, I'll excuse myself since I have to go Brazil and watch some football match. Do you want to request anything?"

"No, I'm okay. Just be safe and enjoy your trip, Koro-sensei." With that, Koro-sensei blasted off.

Koro-sensei was of course once again touched by Tsuna's word. No matter how he looked at the younger, he only saw a kind male and somehow naïve male but behind those masked, he knew Tsuna was anything but dangerous.

Dangerous but in a good way. That made Koro-sensei smiles, knowing that they are still good people out there just like Sawada Tsunayoshi.

* * *

 **A/N:** I hope it's not boring (how is it not boring when I feel boring reading it back =_=") Please leave review/comment on how this story progress so far and what do you think? Is it good or not?

 _Preview Chapter 4_

 _"_ _Why are you standing here? You'll get sick you know."_

 _"_ _Don't show any kindness towards someone who you just meet."_

 _"_ _What do you mean by that?!"_

 _"_ _I won't forgive you!"_

 _"_ _I know how it feels, so don't be sad, Koro-sensei. Smile."_

 _"_ _You really are nice, Tsuna-kun."_

 _"_ _Don't touch Juudaime!"_

 _Preview end_


	4. Chapter 4

**Disclaimer:** I don't own KHR and ACR. Only the plot is mind.

 **Warning!:** Un-Beta, weak in grammar and maybe some typo, SLASH

* * *

 **Chapter 4**

Tsuna dried his hair with a towel as he stepped out of his bathroom; he was currently wearing dark blue slacks but no shirts. He takes the espresso on his hand and walks towards the window where he sits on its sill. As he takes a sip of the espresso, he notices how quiet the house is making it a little bit eerie. Like a ghost probably would pop out of nowhere.

As he thinks more about how the house was too quiet, he remembers how previously, the house would be so loud with Lambo, I-Pin, Fuuta, Bianchi, his mom, Reborn and he would talk and all. The kids would fight and play as they bring him into their fight. He unconsciously grasps the cup too tightly that a crack appears on it.

Even though he got his second chance to atone his past mistake, he feels incomplete without anyone he knew. He wants his guardian to be there with him, so that they can talk hours and hours, he wants his lover to be there, so that they can cuddling all day and didn't care about what happen around them. He also wants his family to be there, so that they can have a nice happy day together.

He knows what he just wishes and wants is something selfish. But he can't help it when the feelings are overwhelming him. He can't bring himself to even forget them for a second since the memories always invades his mind.

He shook his head slowly. Thinking about them will not bring them alive so he had to make sure that he lives well for their share too. He should probably take a look at some information regarding Koro-sensei and maybe he'll find something interesting today.

As he sits in front of his computer, he hacks into the government and look into each files containing about Koro-sensei. But unfortunately, he didn't found much since the government didn't know much about it too and only a couple of knows about his origin. But, this is really making him more curious about Koro-sensei. The conversation he had with Koro-sensei last time shows that he was born and raised on earth.

There's no other creature he had encounter on this world that was the same species with him. Is he a human once but turn like that because of experiment? Nah, maybe not. Tsuna sighed as he stretch his stiff body since he had sit on the same spot for two hours. When he look outside, it's already night. Street lamp was on and no people can be seen walking out there. The places really resemble Namimori much.

But, even though his house was the same, this was not Namimori.

He drags himself from the table after shutting off the computer before literally throw his tired body on his bed. He immediately land on dreamland after a few minutes of closing eyes.

* * *

A few days had passed after he tried researching about Koro-sensei and become a teacher. His bonds with his students even got closer than before that they call even call him either nii-san or just Tsuna-sensei. He even teaches them some move on how to be more precise to shoot or stab at a moving target, of course with Koro-sensei volunteering to be the target – even though he is the real target.

Teaching them something that he never does to any civilians was fun, especially the natural born assassin Shiota Nagisa. Nagisa has the potential on becoming a successful assassin one day, but looking at him right now, Tsuna think Nagisa would never want to become assassin at all. Maybe he'll use them with something useful in the future.

Tsuna admit that all of them are really good in learning new thing that Tsuna had taught them so far. Taking it all like a sponge absorbs water. Dare he says, he's a bit proud of them. IS thisthe feeling each teacher feels when their students made something that exceeds their imagination? Then, he's glad to be called a teacher.

He sighs as he looks upwards. The skies didn't show it brilliantness today. Cumulonimbus cloud are everywhere with the sun being hides behind them. It's probably a storm since the rain had begins to fall on the earth already.

Storm and rain.

Hayato and Takeshi.

His right hand man and left hand man.

He chuckles just by remembering about his two best friends and guardians. The two of them were the one that had always been with him, always standing beside him, protecting him, guarding him even though he just wants to take a walk. They protectiveness sometimes irritated Tsuna but mostly he like their companion since he never feels alone at all. The bickering that happened between them just like Tom and Jerry always made him laugh.

If the two of them are alive in this world, he would go and apologizes no matter how much. He'll apologizes about can't protects them even though they had always protect him, he'll apologizes for not being there when they were in need, he'll apologizes on how he can't prevents them from dying. He'll apologize about everything.

"Mi manchi due la mia tempeste e la mia pioggia."

After he finishes with his monologue, he arrives in front to Class 3-E building. He was about to enter the building when a figure standing just outside of the classroom, looking at the wall, like he's waiting for something. He decided to walk towards the boy. He remembers that Karasuma had mail him on advance yesterday telling him that today; they'll have a transfer student. So, is that the transfer student?

Weird, when Tsuna stand just beside him, he notices on how the boy was not wet even with the pouring day. How did the kid stay dry like that?

"Why are you standing here? You'll get sick you know."

The white hair boy turn to him, his eyes, Tsuna notices, is something that usually can be seen on some assassins that were on killing mission.

"Who are you?"

"Sawada Tsunayoshi, I'm a teacher here. Just call me Tsuna-sensei." Tsuna exclaimed but the boy just look at him indifferently.

"Why are you talking to me? Didn't you know that talking with a stranger is dangerous?"

"Hmm, I don't see how you can be dangerous. I just see a 15 years old boy who in need with something, that maybe you could call loves?"

"..."

"Hahaha... Sorry, that was random; I just want to make you smile is all. So, why don't we go inside and introduce you to the others?"

"I am waiting for an order from my master. Also, don't show any kindness towards someone who you just meet." He said before he walks straight towards the wall, destroying it instantly as he sit beside Karma.

The faces that they made after seeing the entrance of a new student are priceless. They were of course surprised on how unique the transfer student just made. Walking and destroying the wall is not something that you can see every day.

Interesting.

Tsuna can't wait to see how the transfer student will behave. Wait a second? Didn't he say earlier that he was waiting for his master orders? So, then, where is the supposedly master?

Oh, he sees him. Some guy whose hiding behind a cloak. Probably not wanting his identity to be known by them. He admits that he didn't like that guy at all. Just at first glance, he already knows how manipulative the person is just like Asano Gakuho but maybe on another level.

"I... am victorious. I was proven myself to be stronger than this classroom walls. That alone is enough. That alone is enough."

 _"_ _Koro-sensei's reaction is troublesome too! He's not even smiling or being serious... What the heck is with that half-assed face?"_

Tsuna smiles when he read their thought. This is an ability that he learns from Reborn.

"This is Horibe Itona. Please call him by name." The guy in cloak (Tsuna still doesn't know Shiro's name at this time since he come after Shiro's introduction) said. "Oh, and I've spoiled him a bit, so for the time being, please allow me to watch over him."

Meanwhile, Tsuna seeing that the wall had already been destroyed and all decided to enter from there. Safe some time for him since the entrance is a meter away from there (You're being lazy there Tsuna~)

"Ne, Itona-kun, it's kinda been bugging me but, you weren't carrying anything when you came in just now, right?" Tsuna look at Karma. "Tsuna-sensei, did he wear any raincoat or use umbrella outside?" Karma asked him.

"No." Tsuna stared at Horibe. He also wants to know the reason he stays dry when outside it was downpour.

"So why aren't you even the slightest bit wet, when it's pouring outside?"

Horibe glance at the classroom before he stand and walk towards Karma. Since there is no killing intent at all, Tsuna just leaned on the wall, watching the drama to roll on.

"You are probably the strongest one in this class. But don't worry. You're weaker than me. So, I won't kill you."

 _"_ _That's confidence he got there. No one ever talk like that to Karma-kun, not even Terasaka-kun."_ Tsuna thought as he stared at Horibe's back when he started to go towards Koro-sensei whose eating (What did Koro-sensei eat again? I don't know the name of it)

"I think I only want to kill those who might be stronger than me. In this classroom, that means only you Koro-sensei."

"Does that talk of 'strong' and 'weak' refer to fighting, Itona-kun? In a contest of strength, you wouldn't even be able to stand in the same dimension as me, though."

"I can. Because we are brothers related by blood."

The reaction was instantaneous. Koro-sensei with his trademark smiling (or is it grinning) sweat dropped by the exclamation while the students are surprised by it. Tsuna chuckles seeing their reaction but to say that he didn't surprised is nothing, he is surprised a bit though. And after that, a sudden death match between the two brothers had been declared.

* * *

Awkward.

Tsuna can feel the tension in Karasuma and Bitch-sensei aura. The two of them are being careful with this Shiro guy inside of the teacher lounge. While the three of them were talking, Tsuna just watch them from the sides while his mind flew off to the match that will commence after school. He didn't said or shows it but he was disgusted by it. How can brothers calmly exclaimed such thing towards his older brother (Are they even true siblings?)

For Tsuna, killing each other is disgusting, especially family. He despised it. He was not a fond of it at all since he love his family equally, even a simple fight can turn into something ugly. That is why he always stopped his guardians from fighting. A sparing was not counted though.

"Tsuna..."

He turns towards the speaker who broke him from his thought. "What is it, Karasuma-san?"

"Don't you want to see them?"

"Oh, it's already that time. I will follow you later."

Frankly said, Tsuna actually doesn't want to see the match at all. Since it'll lead into something that he didn't want to. His HI had been acting up and that's give him some headache. He really needs his rest today. He was about to take a nap when a 'CRANK' sound and yelling can be heard from the class where Koro-sensei is fighting his supposedly brother, Horibe.

He immediately rushed there just to see Koro-sensei being overwhelming by Horibe whose fighting with tentacles too. Tsuna hate this situation. Horibe's tentacles are waving everywhere when Tsuna saw it goes towards the student especially the girls. He immediately run and jump in front of the girl. With the Anti-Sensei knife on his hand – he takes it from Nagisa, whose holding it, when the boy was distracted.

He makes an upward slash. Horibe widen his eyes as so the others. Koro-sensei was huffing from exhaustion as he also looks at Tsuna, whose hand on the air and tentacles from Horibe's being cut by him.

"I have enough of this ridiculous fight." His bangs shadowing his eyes. "This is not how a family member treated each other."

Tsuna walked towards Horibe who's still surprised by the out coming actions from the brunette when he was lifted and thrown out of the window.

"You already out of the rings, so it's your lose. Stop this fight this instance and apologize."

"You... WHY DID YOU INTERFE..." Horibe was yelling at one second when Shiro shoot him with something that made him unconscious.

"My apologies, Koro-sensei, Sawada-san. It would seem that this boy still had such a mindset which would prevent him from attending school." Shiro walks towards the unconscious boy and lifted him up to his shoulder. "Though this is his first dayafter transferring, he will be taking brief leave of absence." They are surprised by the exclamation.

"Hold on a moment, as his homeroom teacher, I cannot simply let that student leave. Once he joins this class, he will be in my care until he graduates. That aside Shiro-san, there is also a multitude of things I'd like to ask you."

"No way. We're leaving. Do you intend to try stopping me by force?"

Tsuna can see that Koro-sensei is furious with Shiro even though he still had his trademark smiles. When Koro-sensei is about to stop Shiro, Tsuna stop him.

"Don't be hasty, Koro-sensei. We will get that boy eventually, besides you can't touch him. His cloak is made of Anti-Sensei materials."

"It seems you're not an ordinary teacher, Sawada-san." He murmured just enough for Tsuna and Koro-sensei hears it and walks away from the building.

 **(Here, you just have to read at manga or watch anime after the fighting had end since Tsuna is not there)**

Tsuna decided to leave the class for a while to confront Shiro once again. He is not satisfied with what Shiro had done today. So, he'll confront him and ask him some question and get his damn answer. God, he's so pissed right now that he literally wants to obliterate something.

Tsuna go towards the path where Shiro and Itona had gone into. Even though he's pissed right now, he can't stop himself from being curious more on that Shiro guy since his HI had been telling him from the start that the guy is not telling them a true story at all. All about his appearances shows that he is lying. True that when he talks at first, Tsuna was sure that he was saying the truth but when he Horibe Itona said that Shiro was his master, his HI immediately acting up that made his head hurt.

His HI also tells him something about 'Experiments', 'Killing', 'God of death', and 'Lab rats'. He himself doesn't know what his HI was telling him but he want to know about it. So, he intends on confronting the Shiro guy when all the fights between Koro-sensei and Horibe – and maybe him stop.

He follows the two into the forest as soon as the fight had end after Shiro shot Horibe with something that made the boy to faints. When they were far enough from the building, Tsuna made his presence known. Shiro stopped on his track when he finally senses someone was following him. He turn around and observes the tree where he felt someone presence are strong there.

"Come out and show yourself." His voice was rough from earlier.

Tsuna deemed it's enough of playing hide and seeks already as he comes out from his hiding places. He leaned on the tree, hand folded in front of his chest, staring straight into Shiro's eyes. His face shows no emotion at all. It becomes a staring contest between the two of them when Shiro broke it with shooting Tsuna with a gun he hides inside of his cloak.

The bullet lodge in between Tsuna's eyes was what Shiro thinks. But he's wrong because the bullet that should lodge inside of Tsuna's head is in between his point and middle finger. It didn't even faze Tsuna at all. Well, a bullet that came towards him with that speed for him is slow compare to what his tutor, Reborn had shoot at him.

"That's not a greeting I anticipated at all but oh well." He shrugged as he grasps the bullet with his hand. His lips show that he smiles but it didn't even reach his eyes at all where his eyes was staring and observing the guy in front of him.

"Yes~ I thought that there's some bad guy that come to kill me~ so, that's why I reacts like that. Besides, I still value my life~" Shiro said with his playful tone but his posture is rigid indicating that he's nervous. The guy is ready to make a move if Tsuna find something wrong with him and Tsuna knows it all.

"Heh, value your life, huh?" Tsuna said, darkly with a smile.

"Of course~"

"So, tell me, why did you make that kid as one of your lab rats then?"

"Whatever you mean by that." Shiro was surprised that someone or should he say, Sawada Tsunayoshi, someone he didn't recognizes knows about it. Then, did he know about the experiments he had done towards Koro-sensei? "Who are you?" He finally asked.

Tsuna stared at him before a smiled that finally reaches his eyes bloomed on his face, a carefree faces, just like his Rain Guardian, Takeshi.

"Just your everyday teacher, a normal teacher that teaches at Kunugigaoka Class 3-E, also I would very much appreciates if you can release Horibe-kun."

"I thought I had explained it to you earlier and why should I obey you?"

"Itona Horibe had transfer to Class 3-E officially today, so it means he is now one of my student. My number one priority right now is my student's safety of course." He said just like what Koro-sensei had said about his students. Well, they are Tsuna's students too.

"How about no?"

Tsuna smiles immediately turn into something that people really should not see at all. He was forming some sort of KI that made Shiro sweating inside of his cloak. And dare he say, the male in front of him emit some kind of demon aura in front of his eyes.

 _"_ _Is he an assassin?"_

"I should have warn you from the beginning though and you must heed my words, I hate when someone disobey me the most." Tsuna glared at him. Actually, Tsuna didn't hate someone who disobeys him but the situation right now forces him to say something like that. He need Horibe Itona now since he knows the boy is in much pain just because of the tentacles on his head.

Shiro is overwhelm but he didn't back out. "I'm afraid I can't do that but do not worry, we will meet again one day~" With that, he use the beam he had used against Koro-sensei earlier towards Tsuna.

Tsuna block the beam with his hand in front of his eyes as he narrowed his eyes where he saw Shiro with Horibe on his shoulder ran away. As soon as the beam disappears, Tsuna lower his hand to the sides and stared into the space where Shiro just stand.

Yes, he let them get away on purpose. But he will get them next time for sure.

He will.

* * *

 **~Somewhere in Venice, Italy~**

"I expect more from you lot." A disappointed voice said towards the seven people that are standing in front of the guy who is sitting on a mahogany chair. "But, you disappoint me. I thought I told you to kill them all and to not leave any survivors."

"But, they were just children. We ca-can't kill innocent's peo-people..." The only woman in the group stated her reason.

"I don't care about that. This is our famiglia name that is in stake, and me as the Decimo, will not tolerate with any unreasonable reason. You should know that by now, dear Chrome."

The now namely Chrome shifted from her position when someone stands in front her.

"We apologize. We will redeem our mistake, Decimo." The silverette, who is standing in front of the woman – protecting her from the antagonist male stated.

"Good, I expect more from my right-hand man. Dismissed."

All of them immediately exit the room with a heavy heart.

"Hayato..." The ravenette call for his friend, which he apparently realized is trembling with his hand clenching tightly and biting his bottom lips until it bleed.

"That is not Juudaime." He murmured but all of them heard it.

"I know."

"I miss Tsuna-nii..."

"This is not the famiglia that we adore, that we protect. This is not the famiglia."

"Hayato, you should extremely calm yourself down. All of us extremely felt what you are felt right now."

"Hn. (Herbivores, you such a weakling.)"

"Kufufufu~ I don't care about this famiglia. I only want to find Sawada Tsunayoshi."

"Mukuro-nii-sama..."

"I agree with Mukuro." The raventte said. "I want to find Tsuna. This famiglia is not the famiglia that he loves. They are all blood-lust."

"If otouto is alive here and had the memories from our past world, we should extremely find him and protect him."

"Ah, we as the guardian should protect him."

They look upwards where the vast skies are. As one, they voiced what they desired the most.

"Our sky."

* * *

 **~In Class E building~**

Tsuna look out the window. He was checking some of the students work after the encounter he had with Shiro that day when his Hyper Intuition tells him about something brewing far from there.

"Tempesta, Pioggia, Sereno, Nuvola, Nebbia, Fulmine..." Tsuna stand from his chair and walk towards the window where reached out his hand towards the sky.

"I hope you all are okay."

* * *

 **A/N:** Finally! 3,640 word for one chapter! Banzai! Yes, I'm happy that this story finally had a long chapter. I really hope you enjoy this chapter and if you want a certain scenes from ACR to be in here, just review or comment and I'll try to insert it. And don't forget to click the follow/vote button and give love to my story! Thank you for reading and still stick with this story! I appreciate it! See you all again on my next update! Ciao!

 **A/N2:** I'M SO SORRY FOR THE GRAMMAR ERROR AND ALL!


	5. Chapter 5

**Chapter 5**

It was in the middle of night when he open his eyes. He look around and concluded that he was at some kind of jail. Not the normal kind of jail, rather it was a luxury jail. The only thing that made him thought that this place was some kind of jail was because the cuff around his ankle's and left hand.

He can't move at all except for sitting up on the bed.

His blood red eyes narrow.

Didn't he die at the war between Vongola and San Lorenzo? If he's still alive, where is he? Why was he cuffed on the bed, preventing him from moving at all. And where the fuck was his guardian at?

"They're better have a damn good reason." He growls.

But, he can't help it if they're died though. He sighs softly when in that moment a sudden rushes of memories that didn't belong to him come slam to his head.

He groans, laying his head on the pillow. A few minutes after, he finally released a sigh.

A world that didn't belong to him yet his counterparts is or was. Also, it seems that his counterparts had died just a few moments ago. Dying from being poisoned by the current Vongola Decimo who hate his gut.

 _'Hmm, interesting. Than I am taking his role right now.'_ He smirks. "You don't know what hit you, Vongola Decimo, Hiroshi."

And Vongola would never knew what hit them.

As Xanxus the user of Wrath Flame vow to take revenge with what he had done to him and his guardians.

* * *

"A beautiful lady like you should not coerce with this kind of man." The Hitman said while pointing his trademark green black gun on the woman's head. "And also, with the man who have information about someone who is really dear to me." His fedora tilting to the side, an eye watching her in amusement.

The woman tremble in front of him. with only a piece of clothes covering her body that she hold in front of her chest. The man, who was her fiancé, lying dead just beside her. One shot on the head.

"Now, do tell me, why do you want this guy, die?" He said, flicking the orange folder on his hand that had the name of one Sawada Tsunayoshi. The woman didn't answer which made him sighs softly. "A shame to see a lady like you died with a shot on the head." He click the gun, intent to end the woman life soon.

"Wait! The Vongola!"

He narrow his eyes. "Vongola you say?"

"Yes, the Decimo want this guy die! He didn't said why but he strongly urge us to kill him as soon as possible!" The woman said or more like yelled at him. "He said that he's a threat to Vongola and all threat should be remove immediately!"

The man tip his fedora, hiding his expression behind it as he ask one last question.

"This Vongola Decimo, what's his name?"

"Hiroshi. Asada Hiroshi.

 **BANG!**

With that, the woman dead body's join her fiancé on the bed. Red blood pooling around their head, and their body lying there, lifelessly.

"Thank you for the information, milady. Chaos"

* * *

After three hours of resting, Xanxus open his eyes. Heightening his sense, he tried to hear if there's someone standing outside of the room. He smirked after sensing that no one was there at all.

"Weak in defense."

He watched the cuff on his left wrist, and in a matter of second, his wrist was free after he tugged at it with so much force. Half of the cuff still in his hand but he care less about it before he tear the cuff on his ankles with so much ease.

Rolling his wrist, he stared at the red mark.

"You'll pay for what you did. I'll show you how a true Vongola work."

As soon as he said it, he walked towards the door and punch it with a Wrath Flame coating on his fist. The debris flew from there and some of them hitting the window, shattering it into millions. That would totally attract attention.

Wearing a scowl, he walked outside and soon, he heard the sound of running from both sides. Xanxus, with a smirked call forth his flame. He stand there, unmoving. Waiting for some idiot prey.

"You... how..."

He turned towards the voice, scowling as he saw the face of the person who want him died. Who made his guardians suffer and made them take on a suicide job, every fucking time. Even though he didn't show it, he cares for them. His guardians was and is his family. He will not admit it, but it is the truth of how he feels for each of his guardians. An annoying family, that was them.

That's just how the Varia always show that they're care for each other.

"Asada Hiroshi, Vongola's Decimo."

"You should've died!" The Decimo yelled, pointing a finger towards him.

"Tough luck then, kid. My body is just too strong for poison." He said, glancing towards his right where people already pull out their gun and revolver. Some of them using rifle.

The Decimo snarl as he order his men.

"Kill him."

* * *

 **Crack!**

Tsuna look at the glass that had fall to the floor. Tiny shards was everywhere. His intuition had been crazy this past day. Telling him 'Save. Him. Must. Protect. War.' He didn't even know what was it about.

A sigh come from his mouth. Taking the broom, he cleans the floor and check for the second time of any shards left. Satisfying with it, he go to the kitchen to make some food.

Tsuna didn't know when was it, but he really miss the noisiness of his previous home. Where he really felt complete. Where he had a friends, family and someone who he can love. Thinking it now, he prefers that life.

Sighing again, he put the omurice on a plate and turn off the stove. Putting the plate on the counter, he decided to eat on the kitchen.

 _"Oh, that's right. I need to search more about this world Vongola."_ He thinks as he shoves one spoon full of omurice to his mouth.

He remembers one special information that made him want to guffaw. The currents Vongola Decimo was name Asada Hiroshi, an arrogant and selfish person who made Vongola as bloodbath mafia famiglia. Different from what Vongola Primo, Giotto, had want.

Asada Hiroshi also known as the one who have no emotion. He kills what stand in front of him, whether it be a woman, an elder, a child, he only know one thing and that was to kill them for the purpose of completing the mission without remorse.

Also what surprising him with the information he got yesterday, Vongola Nono seems like he was sick, with an incurable illness that no one knows. Meanwhile Xanxus was label as MIA. The other three brothers, Nono's son was unfortunately met their own demised even in this world.

He would love to get to know about them though. He sigh.

But then, what about the guardian of Varia? Where were there? Why did Vongola didn't mention any of them? Tsuna hope wherever they are right now, they'll be safe.

He didn't check any more than that yesterday and he plan on continuing it tonight. He want to know if his guardians exist in this world. He didn't even know if they were in Vongola but it didn't hurt if he checks there first.

Taking one last spoon of the omurice, he realized something.

"Didn't Takaoka said there's a big chance for a new teacher to come tomorrow?"

* * *

 **A/N:** _OMG! It's been like what, a year, two years ago since I update this this story and I'm truly sorry! My muse decides to take a long vacation. And for that I apologize once again. I don't know whether I can update this story regularly but this I promise, I won't abandon this story. I hope I can update this story ASAP. Then, see you all in the next chapter! Enjoy!_

 _-Ciao-_


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